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Ultra-fine grained TA5 titanium alloy was fabricated by friction stir processing (FSP). Temperature distribution and material flow were simulated by the coupled Euler–Lagrange (CEL) method. The microstructure and mechanical properties of TA5 alloy were characterized by optical and scanning electron microscope, Vickers hardness, and tensile tests. The processed alloy was composed of ultra-fine grained and equiaxed grains due to dynamic recrystallization. The microstructure recrystallized through grain boundary rotation and dislocation accumulation. The grain size reached the minimum on the advancing side of the stir zone with the highest grain misorientation. Ultimate tensile strength was promoted to over 830 MPa after FSP at a rotating speed of 200 r/min, whereas elongation varied a little. The specimens all fractured on the retreating side of the stir zone and smaller dimples were depicted from the fracture morphologies of FSP specimens.

The adsorption effects of 3dtransitional metal (TM) adatoms on electronic and magnetic properties of monolayer and bilayer MoS2sheets have been investigated by using first-principle calculations based on the density functional theory. The calculated results suggest that both monolayer and bilayer MoS2sheets have power abilities of absorbing 3dTM atoms. The interlayer adsorption of bilayer MoS2is relatively more stable than the surface adsorption of monolayer MoS2. The 3dTM adatoms and the neighboring S atoms behave a clear covalent-binding character. It was found that TM adatoms induce certain impurity states within the band gap of the pristine MoS2sheet which result in the systems magnetically semiconducting or half metallic. The adsorbed systems for Cr and Co on the surface of monolayer MoS2sheet, as well as Sc, Cr and Fe in the interlayer of bilayer MoS2sheet exhibit half-metallic behavior. And the other 3dTM-adsorbed systems are magnetic semiconductor except for Ni species.

The interaction between H2S and oxygen vacancy on the anatase TiO2(101) surface has been theoretically studied by using first-principles calculations. On one hand, it is found that the relative stability of the subsurface and surface VOcould be reversed by H2S adsorption, and the surface VObecomes energetically more favorable than the subsurface VO. Meanwhile, the adsorption of H2S also can efficiently facilitate VOdiffusion from the subsurface layer to the surface layer. On the other hand, the results show that both the subsurface and the surface VOs can facilitate the H2S dissociation. Subsurface VOcan facilitate the H2S dissociation directly. In contrast, the H2S dissociates on the surface with surface VOby two indirect pathways. Specifically, after H2S dissociation on the surface with surface VO, the adsorption of the two complete dissociative H2S are energetically more stable than that of the surface with subsurface VO, and the sulfur atoms from H2S fill in the surface VOsite and form stable S-doped TiO2surfaces. This conclusion reveals the essential interaction between H2S and a subsurface oxygen vacancy, which may provide a possible way to illuminate the origin of the photocatalytic activity of the anatase TiO2(101) surface, and offers a possible method to obtain the S-doped TiO2surface.

As one of the most prolifically produced plastics in the world, poly(vinyl chloride) (PVC) suffers from mechanical brittleness and low toughness. Compared with traditional phthalate-type plasticizers, poly(ε-caprolactone) (PCL)-based plasticizers are especially attractive due to their “green” nature and capabilities to achieve improved physical properties. Herein, a stretchable and ultratough PVC-based plastic was achieved by a star-shaped PCL copolymer with a rigid, amino-containing, branched polylactide (N-BPLA) core and a soft PCL shell, that is, RN-SPCLs. With an optimal feed ratio of the CL monomer and N-BPLA core, the RN-SPCL2 can efficiently lower the glass transition temperature (Tg) of PVC plastics, achieving the transition from the “glassy” to “rubbery” state at ambient temperature. The obtained RN-SPCL2/PVC not only shows high extensibility, that is, 453%, but also maintains close to 80% of tensile strength of neat PVC, that is, 30.1 MPa, which is much higher than the previously reported plasticized PVCs. Its overall toughness reaches 92.7 MJ/m3, being more than 50-fold higher than neat PVC and 2 to 3 times higher than linear PCL or dibutyl phthalate plasticized PVCs. The important role of star-shaped architecture with a rigid core and flexible PCL shell for RN-SPCL2 in achieving highly stretchable and ultratough PVC plastics is systematically investigated. More interestingly, the as-prepared RN-SPCLs also endow PVC plastics with photoluminescence property and allow homogeneous dispersion of nanosized TiO2for significantly enhancing the anti-UV capability.